P CODES (POWERTRAIN) P0400 - P0499 P0420

Hi, My Car Keeps Throwing A P0420 Code On My Code Reader, But No Engine Light Is On. Should I Be Worried? How Can I Diagnose The Fault...

Code P0420 Catalyst System Efficiency Below Threshold (bank 1 ). How Do I Correct This Problem

I Have A 2001 Gmc Sonoma 2wd 2.2 Liter And Have The P0420 Code For Catylyst Efficiency Low Bank One. I Have A New Cat And Rear O2 Sensor So...

Hello Everyone, I Scanned My Car And The Error Code Is P0420. The Catalytic Converter Has Been Changed. The The Manifold Was Cut Open And...

I Have A 2000 Mazda 626 V6. For The Last Couple Of Years The Check Engine Light Comes On With A P0420. It Might Come On For A Couple Of Days...

Good Afternoon, My 2004 Grand Am Has A P0420 Code. I Replaced The O2 Sensor That Is In The Exhaust Manifold. The Dealership Told Me That...

After I Replace My Spark Plugs With Champion Platinums 7940 And Spark Plug Wirers. I Had An Issue With Bad Wire On Number 5 Cylinder, And...

Ses Has Been On Since Vehicle Was Purchased 2 Months Ago, But Have Had No Driveability Concerns Until Now. When Cars Mpg Is Decreasing And...

Hello, I Need To Put Two New Catalytic Converters On My Truck? I Believe The Codes Were P0420 And P0430. There Were No Other Codes...

I Have 03 Jetta With Rebuilt Engine Just Installed And P0420 Code Pops Up. So I Replace Both O2 Sensors And New Cat. What Should I Do Next...